This invention relates to piezoelectric oscillators comprising a piezoelectric element and a casing, and is more particularly concerned with an oscillator, for use in e.g. a timepiece, in which the casing includes a pair of glass plates which are sealed to one another and whose insides are formed with recesses defining a housing for the piezoelectric element and defining a pedestal for the latter.
The manufacture of such oscillators has not so far been trouble-free. Attempts to seal the two glass plates with adhesive have been unsatisfactory because the adhesives available are too permeable to maintain for long enough the vacuum required by these oscillators. Attempts have also been made to seal the two plates with a metal solder but the solder crosses a pair of electrically conductive tracks acting as terminals for the piezoelectric element, hence the need to provide intermediate insulating material of sufficient width to avoid a short-circuit through the solder, thereby substantially increasing the volume of the casing.